Scanning electron microscope

Abstract

In order to provide a full-automatic scanning electron microscope which carries out investigation jobs full-automatically from fine adjustment to reviewing, the scanning electron microscope of the present invention has a function of calculating the accuracy of correction after correction of coordinates and displaying it with vectors 39 , a function of automatically determining a searching magnification for automatic object detection from the obtained information after correction of coordinates, and a function of calculating the frequency of occurrence of objects or defects and a time required for measurement from the searching magnification and conditions of measurement.

1. A scanning electron microscope comprising:
 a cathode; 
 a scanning deflector for scanning an electron beam generated from said cathode on a specimen; 
 an objective lens for converging said electron beam on said specimen; 
 a detector for detecting secondary electrons generated from said specimen; 
 a display device for displaying an image of said specimen based on an output of said detector; 
 a moving stage for moving said specimen; and 
 a control device for displaying areas whose object of interest obtained from another device is automatically selected for fine adjustment on the display device, for calculating a corrected coordinate value of said object of interest obtained from another device by using a coordinate correcting expression for correcting an error between a coordinate of said another device and a coordinate of said moving stage, and for moving said moving stage based on said corrected coordinate value, wherein: 
 said control device moves said moving stage and adjusts a position of said object so as to move said object of interest to an observing position being observed by said electron beam, and calculates a vector of misalignment with coordinates of said object whose position was adjusted. 
 
   
   
     2. A scanning electron microscope in accordance with  claim 1 , wherein said coordinate correcting expression is set to minimize the difference between coordinate values of objects of interest on said specimen which were obtained by another device and coordinate values of said objects in the coordinates system of the stage which are actually observed. 
   
   
     3. A scanning electron microscope in accordance with  claim 1 , wherein said coordinate correcting expression is to convert the coordinates system on said specimen to the coordinates system on said stage for measurement of coordinate values of some pre-selected points on said specimen in the coordinates system of said stage. 
   
   
     4. A scanning electron microscope in accordance with  claim 1 ,  2 , or  3 , wherein said scanning electron microscope further comprises a function which calculates a difference vector between a position vector representing coordinates at which said point of interest is actually observed and a position vector representing said corrected coordinates, and displays the equivalent difference vector on the position of said object of interest for visual indication of said accuracy of correction. 
   
   
     5. A scanning electron microscope in accordance with  claim 4 , wherein said objects of interest are foreign objects or defects on the specimen and said scanning electron microscope further comprises a function which automatically determines a magnification to automatically move said stage to said corrected coordinates and detects foreign objects or defects according to their sizes and said accuracy of correction. 
   
   
     6. A scanning electron microscope in accordance with  claim 5 , wherein said scanning electron microscope further comprises a function which calculates a frequency of occurrence of objects or defects which are automatically detected at a determined magnification. 
   
   
     7. A scanning electron microscope in accordance with  claim 6 , wherein said scanning electron microscope further comprises a function which calculates a time period for measurement from the calculated frequency of occurrence, a condition of measurement, and the number of objects or defects.